1. Field of the Invention
The invention relates to a device for determining and characterizing noises generated by mastication of food, wherein the device comprises a mastication device and at least one reception microphone.
2. Description of the Related Art
A device of the aforementioned kind is known. Recently, the food industry has found it to be advantageous to consider the chewing or mastication noises generated by food in order to improve sales, and, consequently, the Nestlxc3xa9 Research Center, for example, has developed a so-called acusto-mechanical device for determining and characterizing the so-called crispness, i.e., the noise developed during mastication of food.
In this context, crispness is considered a quality feature for texture, wherein the texture is the entirety of impressions which are sensed when food is touched, cut, spread, pricked, poured, bitten into, or chewed and swallowed.
It is known that food often has a heterogeneous structure, i.e., a macro structure as, for example, bread crumbs or the crust of bread.
The texture, however, indicates a structure that is xe2x80x9cinvisiblexe2x80x9d because these structural units are microscopically small.
The sensations which occur during a texture determination can be differentiated as follows: soft, solid, hard, crumbly, crisp, brittle, smooth, rubber-like tacky, pasty, slippery; as well as clear, viscous, slimy; and also sandy, grainy, coarse, fibrous and crystalline.
The so-called crispness is an important sensory quality feature of the texture of the product.
This crispness is often a desired feature of various foods, for example, breakfast cereals, sweets, baked goods, vegetables, fruits, and others.
The Nestlxc3xa9 company was able to determine crispness with the aid of the aforementioned acusto-mechanical device.
In this connection, the food to be examined was crushed or masticated by means of a masticator, and the noise resulting therefrom was recorded by means of a microphone.
However, in this connection only the so-called airborne sound was recorded, but not the noises which are conducted during chewing via the bones into the inner ear, the so-called bone-conducted sound.
This has the consequence that this device cannot determine or characterize a complete impression of the noises occurring during chewing.
Further methods for determining and characterizing the mastication noises reside in that test persons chew the foods to be tested and evaluate the noises that are caused by the chewing action.
This is not only very time-consuming because each test person requires approximately six minutes to complete each test run, but of much greater consequence is the fact that all test persons report different, i.e., substantially subjective, sensations, so that the test results are not at all reproducible.
It is an object of the present invention to provide a method of the aforementioned kind which makes possible a simple, near-natural, inexpensive determination and characterization of mastication noises of foods.
In accordance with the present invention, this is achieved for a device of the aforementioned kind by an enclosure in which the mastication device as well as the at least one reception microphone are arranged.
This makes a near-natural determination of the mastication noises possible.
In order to improve the simulation of human sensation even further, it is advantageous when a further reception microphone is provided.
According to an especially advantageous embodiment of the invention, the enclosure is a Kunstkopf (dummy head) for audio recording.
In order for the bone-conducted sound to be simulated as identically as possible, it is advantageous when two additional (second) reception microphones are used which are designed such that they receive sound introduced into solid materials, while the two other (first) reception microphones are designed to receive the airborne sound.
Since after comminuting the food it is mainly the tongue that is active during the chewing process, it is advantageous to provide a chewing device for simulating the tongue action during the chewing process.
This chewing device can be a membrane which is actuated electrically, mechanically, pneumatically or is loaded (actuated) by a liquid.
According to a further embodiment of the invention, it is proposed to correlate or pair each additional (second) reception microphone with one of the two other (first) reception microphones, respectively, and to acoustically decouple the correlated (paired) reception microphones.
Moreover, it is possible to connect each of the additional (second) reception microphones by means of an acoustic bridge with a testing chamber in which the mastication device is arranged in order to simulate the bone conduction of sound even better.
Since during a chewing process salivation also plays a role in affecting the acoustics, it is advantageous to provide a moistening device for moistening the food.
Moreover, it is possible to ensure the acoustic conditions to be even more near-natural by providing a heating device for appropriately heating the food.
When a closeable opening is present, the simulation of the chewing process for an open as well as a closed mouth is possible.
According to a further embodiment of the invention, a control device is provided for controlling the determination and characterization process. This control device can be actuated manually or can perform the control function automatically.
For processing the acoustic measuring results, a processing unit can also be provided.